Wireless communications operating according to a predetermined protocol have gained worldwide popularity. The advantages of the wireless medium include the capacity to address broad geographic areas without expensive infrastructure development such as running cables. The broadband wireless access industry is guided by IEEE standard 802.16 for wide area networks.
Worldwide Interoperability for Microwave Access (WiMAX) is a wireless communications technology for providing wireless data based on the IEEE standard 802.16. A WiMAX network provides an alternative to cabled access networks, such as a digital subscriber line (DSL). In addition, the WiMAX technology may provide fixed, nomadic, portable, and mobile wireless broadband connectivity to a base station. 
The IEEE standard 802.16 supports a multicast/broadcast service (MBS), which can provide service data to a plurality of users who desire to receive the same service in the WiMAX network. For example, the service data may be movies, games, or TV programs, and is usually stored on one or more MBS servers. A user terminal, such as a mobile phone or a laptop, subscribing to an MBS may receive data relating to the MBS through access to one or more base stations (BSs) in the WiMAX network.
For example, a plurality of BSs located in a geographic area each may transmit the data relating to the MBS based on the same multicast connection identifier (MCID). Typically, the plurality of BSs are in the same MBS zone. An MBS zone is a set of BSs in a geographic area which use the same MCID to transmit data relating to one or more MBSs. The advantages of the MBS zone include that the user terminal may receive signals from ones of the plurality of BSs in the MBS zone simultaneously. This would provide a diversity gain and performance improvement for the received signals. Further, the user terminal may receive the data relating to the MBS from any one of the plurality of BSs in the MBS zone without requiring a handover.
Typically, an MBS is associated with a multicast Internet Protocol (IP) address. Internet Protocol version 4 (IPv4) provides 228 multicast IP addresses. Therefore, theoretically, IPv4 may support as many as 228 MBSs. In reality, there may be hundreds of MBSs provided by service providers. However, there are only 94 available MCIDs according to the IEEE standard 802.16. If an MCID is allocated to only one MBS, the available MCIDs may not be enough to support the hundreds of MBSs. 